Bumped Tape Processing and Application

The object of this research was to develop an inner-lead bonding technique for making multiple thermocompression bonds between gold-plated copper bumped tape leads and standard aluminum integrated circuit chip bonding pads. An experimental technique was developed to arrive at the optimum bonding parameters for a given set of bonding conditions that include the aluminum bonding pad thickness, copper bump size, copper alloy, and initial copper hardness. A laboratory inner-lead bonding machine was modified to enable it to make dynamic measurements of the chip temperature response and bonding force. Bonding parameters were evaluated with destructive pull tests. The results indicate that each combination of chip design and tape design requires unique bonding machine settings to achieve the proper combination of temperature and compressive stress at the gold/aluminum interface.